The Council of Trade Unions says a broad-based capital gains tax would not be a miracle cure for the economy but would result in an overall fairer system.
CTU secretary Peter Conway participated in the Tax Working Group and says the Labour Party's plan, if elected to Government, would result in higher Government revenue and make houses more affordable.
Labour's capital gains tax would extend to investment properties, the sale of businesses, shares and individual assets, but would exclude the family home.
Mr Conway does not think people with investment properties would be unfairly penalised by the tax.
He says people who earn extra money from their job are taxed, therefore those who get additional income from property investments should also pay tax.